Received: 14 May 2020
Revised: 9 October 2020
Accepted: 25 November 2020
First Online: 7 January 2021
Ethical approval and consent to participate
: Ethical approval was not sought for this study because all data came from the summary statistics of published GWAS, and no individual-level data were used.
: Not applicable.
: Genetic instruments can be obtained through MR-Base or from published work.<sup>23,24</sup> Details and availability of CRC genotyping data that support the findings of this study have been previously published.<sup>26</sup>
: One of the co-authors, Richard S. Houlston, was a senior subject editor at the British Journal of Cancer during the peer-review process.
: This work was supported by grants from Cancer Research UK (C1298/A25514, C348/A12076, C6199/A16459, C348/A18927), EU COST Action (BM1206) and the US National Cancer Institute (UM1 CA167551), by a Project Leader grant within the Medical Research Council Human Genetics Unit Centre (Edinburgh, UK, U127527198) and through cooperative agreements with the Australasian Colorectal Cancer Family Registry (U01 CA074778 and U01/U24 CA097735), the Ontario Familial Colorectal Cancer Registry (U01/U24 CA074783) and the Seattle Colorectal Cancer Family Registry (U01/U24 CA074794). Support was also provided by the DJ Fielding Medical Research Trust.